Activity 和 Fragment 中可以实现的 DialogFragment 接口
DialogFragment Interface that Can Be Implemented in Activities and Fragments
我的 ListFragment
有一个 ListItem
的上下文菜单。菜单选项之一用于删除项目,我想向用户显示一个确认对话框以防止意外删除。
public class MyListFragment extends ListFragment implements ConfirmDeletePopupFragment.DialogListener {
(...)
@Override
public boolean onContextItemSelected(MenuItem item) {
switch (item.getItemId()) {
case R.id.action_delete:
ConfirmDeletePopupFragment fragment = new ConfirmDeletePopupFragment();
fragment.show(getSupportFragmentManager(), "tag");
return true;
case R.id.action_cancel:
return true;
default:
return super.onContextItemSelected(item);
}
}
}
对于类似情况,我创建了一个通用确认对话框作为 DialogFragment
,如下所示。我可以用它来让用户确认任何关键操作。为了在 Activity
中使用,它有一个带有方法 onDeleteConfirm
的接口,用于处理创建对话框的 Activity
中的实际删除。
public class ConfirmDeletePopupFragment extends DialogFragment {
(...)
@Override
public void onAttach(Activity activity) {
super.onAttach(activity);
try {
mDialogListener = (DialogListener) activity;
} catch (ClassCastException e) {
throw new ClassCastException(getTargetFragment().toString() + " must implement ConfirmDeletePopupFragment.DialogListener");
}
}
@Override
public Dialog onCreateDialog(Bundle savedInstanceState) {
final android.app.AlertDialog.Builder dialogBuilder = new android.app.AlertDialog.Builder(getActivity());
final LayoutInflater inflater = getActivity().getLayoutInflater();
final View dialogView = inflater.inflate(R.layout.popup_confirm_delete, null);
dialogBuilder.setView(dialogView);
dialogBuilder.setTitle("Delete?");
dialogBuilder.setNegativeButton(getString(R.string.activities_confirm_deletion_cancel_button), new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int whichButton) {
}
});
dialogBuilder.setPositiveButton(getString(R.string.activities_confirm_deletion_delete_button), new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int whichButton) {
((DialogListener) getActivity()).onDeleteConfirm();
}
});
deleteDialog = dialogBuilder.create();
deleteDialog.show();
return deleteDialog;
}
public interface DialogListener {
void onDeleteConfirm();
}
}
显然,此接口仅在 Activity
(((DialogListener) getActivity()).onDeleteConfirm();
) 中创建对话框时有效。对于上面提到的问题,我需要从 Listfragment
中创建对话框,而仅在 ListFragment
中实现对话框界面不起作用 ("Activity must implement ConfirmDeletePopupFragment.DialogListener")
什么是调整我的 DialogFragment
的最佳方式,以便它适应两种情况(在 Activity
或 Fragment
中创建)?
显示对话框时(片段):
<dialog>.setTargetFragment(<your fragment>);
<dialog>.show();
在activity中跳过setTargetFragment。
在 DialogFragment 代码中:
@Override
public void onAttach(Activity activity) {
super.onAttach(activity);
if (getTargetFragment() != null) {
myInterface = (YourCastInterface) getTargetFragment();
} else {
myInterface = (YourCastInterface) activity;
}
}
我的 ListFragment
有一个 ListItem
的上下文菜单。菜单选项之一用于删除项目,我想向用户显示一个确认对话框以防止意外删除。
public class MyListFragment extends ListFragment implements ConfirmDeletePopupFragment.DialogListener {
(...)
@Override
public boolean onContextItemSelected(MenuItem item) {
switch (item.getItemId()) {
case R.id.action_delete:
ConfirmDeletePopupFragment fragment = new ConfirmDeletePopupFragment();
fragment.show(getSupportFragmentManager(), "tag");
return true;
case R.id.action_cancel:
return true;
default:
return super.onContextItemSelected(item);
}
}
}
对于类似情况,我创建了一个通用确认对话框作为 DialogFragment
,如下所示。我可以用它来让用户确认任何关键操作。为了在 Activity
中使用,它有一个带有方法 onDeleteConfirm
的接口,用于处理创建对话框的 Activity
中的实际删除。
public class ConfirmDeletePopupFragment extends DialogFragment {
(...)
@Override
public void onAttach(Activity activity) {
super.onAttach(activity);
try {
mDialogListener = (DialogListener) activity;
} catch (ClassCastException e) {
throw new ClassCastException(getTargetFragment().toString() + " must implement ConfirmDeletePopupFragment.DialogListener");
}
}
@Override
public Dialog onCreateDialog(Bundle savedInstanceState) {
final android.app.AlertDialog.Builder dialogBuilder = new android.app.AlertDialog.Builder(getActivity());
final LayoutInflater inflater = getActivity().getLayoutInflater();
final View dialogView = inflater.inflate(R.layout.popup_confirm_delete, null);
dialogBuilder.setView(dialogView);
dialogBuilder.setTitle("Delete?");
dialogBuilder.setNegativeButton(getString(R.string.activities_confirm_deletion_cancel_button), new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int whichButton) {
}
});
dialogBuilder.setPositiveButton(getString(R.string.activities_confirm_deletion_delete_button), new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int whichButton) {
((DialogListener) getActivity()).onDeleteConfirm();
}
});
deleteDialog = dialogBuilder.create();
deleteDialog.show();
return deleteDialog;
}
public interface DialogListener {
void onDeleteConfirm();
}
}
显然,此接口仅在 Activity
(((DialogListener) getActivity()).onDeleteConfirm();
) 中创建对话框时有效。对于上面提到的问题,我需要从 Listfragment
中创建对话框,而仅在 ListFragment
中实现对话框界面不起作用 ("Activity must implement ConfirmDeletePopupFragment.DialogListener")
什么是调整我的 DialogFragment
的最佳方式,以便它适应两种情况(在 Activity
或 Fragment
中创建)?
显示对话框时(片段):
<dialog>.setTargetFragment(<your fragment>);
<dialog>.show();
在activity中跳过setTargetFragment。
在 DialogFragment 代码中:
@Override
public void onAttach(Activity activity) {
super.onAttach(activity);
if (getTargetFragment() != null) {
myInterface = (YourCastInterface) getTargetFragment();
} else {
myInterface = (YourCastInterface) activity;
}
}